At present, a liquid crystal display panel includes a matrix of pixels, and in a display process, a gate driver circuit is controlled to output gate scanning signals, thereby realizing progressive scanning to access respective rows of pixels, and realizing image display in cooperation with image data.
The gate driver circuit is configured to generate a gate scanning voltage for a pixel, while Gate driver on Array (GOA) is a technique in which the gate driver circuit is integrated with an array substrate. In the gate driver circuit, each GOA gate driver unit as a shift register successively transmits scanning signals to the next GOA gate driver unit, so as to switch on thin film transistors (TFTs) row by row, thereby completing input of data signals to each row of pixel units. As a kind of particular gate driver circuit, GOA bi-directional scanning circuit can control the gate scanning signals to realize forward scanning or backward scanning by only changing the timing sequence of input signals, without changing the physical structure of GOA gate driver unit.
An oxide thin film transistor (Oxide TFT) display panel is a display panel in which a semiconductor layer of TFTs is made of a metal oxide material, and has advantages such as high electron mobility, large aperture ratio and the like. However, in conventional GOA gate driver units, a gate of a thin film transistor operates in a low voltage state for a long time, which easily leads to changes in its characteristics, experiencing a threshold voltage Vth drifting phenomenon. Particularly, Oxide TFT is liable to be affected by a single bias voltage, so that the stability of GOA gate driver unit becomes poor in a long display process of a display panel, thereby disturbing the output of regular scanning signals.
From above it can be seen that designing a GOA gate driver unit with simple structure and capable of maintaining the stability of TFTs becomes a technical problem to be solved urgently in the art.